Conversion of carbonaceous solids into valuable liquid products



April 18, 1933. K. 'WINKLER ETAL a 1,904,536

CONVERSION OF CARBONACEOUS SOLIDS INTO VALUABLE LIQUID PRODUCTS Filed Dec. 15', 1927 compresslon am o Jaw/12m BY Kurt M'SSEZ JW M ATTORN EYS Patented Apr. 18, 1933 UNITED STATES PATENT OFFICE KARL WINKLEB AND KURT WIBSEL, F LUDwIG sflAFflN ofl-TflE-mn GERMANY,

ASSIGNORB 1'0 I. G. FABBENINDUSTBIE AKTIENGESELLSCHAFT, OI FBANKFOBT- ON-THE-IADI, GERKANY, A CORPORATION OF GERMANY CONVERSION OF CABBONACEOUS SOLIDS INTO VALUABLE LIQUID PRODUCTS Application med December 15, 1927, Serial no. 240,383, and in Germany December 22, 1928.

In the process of low temperature car bonization of solid bituminous materials a large proportion of the said materials is'converted into diflicultly condensible gases at the 5 expense of the yield of tar.

We have now found that an excellent yield of liquid products and of products which liquefy when warm i. e. at temperatures not much above ordinary temperature are obtained, and the formation of gases, and especially such gases as condense with difliculty, is prevented to a large extent, by treating'the solid initial materials in the absence of substantial amounts of added hydrogen with high boilin hydrocarbons or hydrocarbons having'a high molecular weight, which expression is also understood to comprise the derivatives thereof, containing substantially no constituents boiling below 300 (1., in a suitable pressure. chamber, if desired with the joint use of gases containing for example nitrogen, carbon dioxid or carbon monoxid but free from considerable amounts of hydrogen, and/or the joint addition of catal tic substances, such for example as su stances with alkaline reaction, in articular the sulfids of the alkali metals an alkaline earth metals, at temperatures below the coking temperature of the added hydrocar- 3o bons or their derivatives, in a continuous manner and under elevated pressure, preferably very high pressure, for such a riod of time that the yield of valuable hy rocarbons or hydrocarbon derivatives becomes a multiple of that,obtained by ordinary low temperature carbonization. By continuous treatment is meant the continuous introduction of the materials to be treated and the continuous removal of theproducts of the 40 process. I

The employment of inert gases is particularly advantageous since these loosen up the material under treatment and since they may also increase the pressure on the material and since on account of their diluent action they allow of a more rapid running through of the materials.

The addition of the aforesaid catalytic crease the speed of the operation and the resulting yields. The amounts of catalyst used are not critical for the improved result. Improved results are obtained even with very small amounts of" catalyst, and amounts considerably larger than those required for securing a desired degree of improvement have no detrimental eifect. In practice the catalyst is employed in an amount of about from 3 to 7 per cent of the weight of the mixture of coal and oil treated. A great variety of solid bituminous initial materials may be employed according to thenew process, as for example difierent kinds of coal, such as pit coal or brown-coal of varied origin and character, even that-which has already been deprived of bitmnen by extraction, as well as bituminous shales, peat, wood and the like.

The added oils comprise high-boiling hydrocarbons or hydrocarbons of high molecular' weight, or their derivatives, of the most varied origin and nature. Suitable materials are for example liquid hydrocarbons or their derivatives or those 1i uefying when warm, which are substantiallydree from constituents boiling below 300 C. and which are obtained from any varieties of coal, tars, mineral oils and the like, their distillation and conversion product and residues, as for example by cracking, destructive hydrogenation and other like methods. .Use

may also be made, for example, of high boiling products such as are prepared synthetically from hydrogen and oxids of carbon and the like, and of course the products ob tained in the process of the present invention itself may also be employed. Moreover, oils of different kinds may be employed in succession or in association. In addition to the high-molecular added oils, use may be made of gases such as nitrogen, ammonia, carbon dioxid, water vapor, and the like. At the temperatures and pressures employed according to the present invention no substantial dissociation of ammonia or water into their elements occurs, so that substantially no hydrogenation takes place. Other additions may also be made which have a beneficial physical or chemical action, such as distributive, thermoconductive or catalytic action, during the process.

The temperature must be regulated according to the substance employed and may vary for different materials. Elevated temperatures may be employed without however exceeding the coking temperature of the added oils under the specified working conditions. In many instances, the most favorable working temperature may be about 300 C. but higher and lower temperatures may also be employed, a temperature above 250 0. being generally suitable. It is frequently advisable to commence with lower temperatures and subsequently to work with higher temperatures. The choice of the added oil depends on the temperature employed, but one and the same initial material may be treated at different temperatures with dif-v ferent added oils, but the oils employed at higher temperatures should preferably be more stable.

The operation is conducted under a pressure of at least 10 atmospheres, very high pressure, as for example above 50 atmospheres and even above 100 atmospheres being preferred. Far higher pressures, for example 1000 atmospheres and more, may also be employed and it may be advisable to operate with different stages of pressure, as for example low pressure during the first stage and then higher pressure during later stages. But in cases where the extraction treatment is followed by a further decomposition treatment, such as cracking or destructive hydrogenation, the process may :be conducted at pressures of down to- 10 atmospheres. The choice of the pressure depends, inter alia, on the temperature selected, which in turn depends on the character of the initial materials and the added oils.

The result obtained by operating in this manner is that, in contrast to low temperature carbonization, the formation of gases,

especiallygases which are. diflicult to con,-

dense, is greatly reduced and the yield of liquid products, or products which become liq- "be employed as the initial material, the yield of liquid products, or products which become liquid when warm, is many times the'amount corresponding to the bitumen which can be extracted from the initial material by benzene. I

As much as 65 per cent of valuable liquid products may be recovered from coals which are even low in bitumen, and alder wood, for example, may be almost completely converted into liquid products by treatment in conjunction with anthracene oil.

The process herein described may be carried out in a continuous manner, for example by mixing the initial material/into a paste with the added oil, forcing it by means of pumps through high pressure vessels provided with stirrers, and then releasing the pressure. The stirring may also be effected by means-of gases. Other measures may also be adopted to obtain a high relative movement between the added oils and the solid initial material, as for example by creating fresh reaction surfaces by mechanical reduction, kneading and other like means. The product or mixture may also be injected into the reaction vessel in a finely divided state. a

The solid bituminous materials and the liquid hydrocarbons may also be passed, in the form of a paste, at a relativelyhigh linear velocity, through a highpressure coil, to effect a suflicient period of contact between said materials to obtain the desired extraction. It is sometimes advisable to pass the mass several times through the apparatus. The continuous operation may also be carried out by mounting a number of vessels, in series or parallel, through which the added oil is passed, some of them being disconnected for recharging with the solid material. and then connected up again, the added oil being brought 'into action, as desired, by stirring. At the end of such a battery of vessels,

units charged with fresh material are connected up in the same proportion as units at the other end are disconnected. Whereas in the cases before mentioned in which the hydrocarbons and solid bituminous materials are formed into a paste and passed together through the system, it is usual to employ unidirectional flow, it is in this case preferable to employ the counterflow principle, the ad vantages being that the fresh added oil is brought into contact with initial material which has already been exposed to extensive treatment.

The heat of the resulting products may be advantageously utilized by transmission to- .The residual coal is 0 the incoming material. The initial materials may also contain Wat r, the drying of the coal being adapted to e combined with the recovery of oil. 1

The product obtained is removed from the pressure chamber, and may, at the same time, under certain circumstances, be quickly relieved of pressure and cooled. After being subjected if required to a preliminary mechanical treatment such as centrifuging and the like, the liquid products are separated from the solid residues in any known and convenient manner, as for example by low temperature carbonization in the presence of steam or other gases and vapors, if desired, extraction or both, or by other means, with or without the application of pressure.

The product obtained, or components of the same may be subjected to cracking in the presence or absence of water vapor or carbon dioxid or another gas or treatment with hydrogen or gases containing the same, with or without the application of pressure, and if desired, with catalysts. In this way, products are obtained of the nature of heavy oils, middle'oils, and li ht oils or benzines. very loose texture, is easily ignited and readily adsorbs gases. It can be transformed into liquid products by treatment with hydrogen under pressure.

The products obtained by means of the process according to the present invention from an earlier charge may be employed either as they are or after further treatment for application as triturating media for the solid carbonaceous material in the presentprocess, as lubricating oil, Diesel oil or engine fuel and the like, either alone or in admixture with other substances.

In carrying out the process it is advisable to see that the material of the apparatus is free from substances which may induce the formation of coke or troublesome viscous masses.

should not be present in such hot portions of the apparatus, especially those parts heated to above 300 C. which come into contact with the substances under treatment. The invention will be further illustrated with reference to the accompanying drawing in which a plant for carrying out the process according to the present invention is illustrated diagrammatically, partly in vertical cross section, although the invention is not limited thereto. a is ahopper through which finely divided solid carbonaceous materials can be introduced into a mixing vessel p; b is a pipe for the introduction of solvent hydrocarbons into the said vessel p. c is a stirrer which is actuated by rotation of the wheel 0 the rotation being transferred by means of the tooth gear m to the shaft n. d is a pipe for the transference of the liquid mixtures prepared in the vessel 1) to the For example, it is advisable that finely divided, or porous, iron and nickel,

pressure resistant coil f which is constructed of alloy steel. 0 is'a pump assisting the said transference. gis a cooler for cooling the products issuing from the coil 7. i is a. pressure release valve'for releasing the pressure on the said products. It is a settling tank from which the li uid products can be removed by means 0 the pipe is, whereas the solid zmixtures are removed by means of the The following examples will further illustrate how the said invention may be carried into practical effect but the invention is not limited thereto.

Example 1 Pulverized brown coal, containing 4 per cent of bitumen which can be extracted by benzene, is made into a paste with 'an equal amount of anthracene oil containing only a small. proportion of constituents boiling be low 300. The mixture is pumped continuously at about 325 C. and under a pressure of 200 atmospheres, through a high pressure vessel, provided with stirring means and constructed internally of highly alloyed steel, a suitable velocity of flow being maintained. After the pressure on the treated coal paste has been relieved, the latter is treated with thinner oil or benzene, or the like, the'resulting productsbeing separated'from the solid residue. In this way, and practically without any formation of gas, per cent and more of the coal, with reference to ash and water-free initial substance, is transformed into high boiling oils which are liquid at ordinary temperature or when warm. The yield may be further in-. creased by the employmentof still higher pressures, for example up to 1000 atmospheres, whereas it becomes considerably smaller if the pressure be substantially reduced, as for example at 20 atmospheres.

Crude brown coal'may be replaced, with equal results, by predried brown coal, containing, for example, 10 per cent of'moisture, or a brown coal which is substantially richer in bitumen. I I

' The recovered products may be employed, either by themselves or in conjunction with anthracene oil, as trituration media for fresh initial materials, or they may be worked up further into lubricating oil, Diesel oil, 'engine fuels and the like.

The initial material may also be introduced into the high-pressure chamber through air locks.

Ewample 2 being continuously introduced. The paste,

' the said coil arecooled down by means of the cooler g. The pressure on the said products is released by means of the valve '5 and I. with a brown coal low temperature tar, which they are passed into the separating vessel It. The solid materials settling down in the said vessel are drawn off at Z and the supernatant oil is drawn off through a valve In. Any oil floating above the'sediment can then be almost completely separated from solid constituents, as for example in a centrifuge.

The traces of oil still adhering to the residue can be recovered, for example, by extraction with benzene, and the like, or by steam distillation. More than 55 per cent of the coal is liquefied without any noteworthy production of gas.

I Example 3 s An oil shale is continuously treated, at 200 atmospheres pressure and at about 320 C.

has been freed from constituents boiling below 300 C. 90 per cent and more of the total carbonaceous substance, free from ash and moisture, is obtained in the form'of oils.

What we claim is:

1. The process for recovering valuable liquid products from solid bituminous materials which comprises treating .said solid materials, in the absence of substantial amounts of hydrogen, with liquid hydrocarbon materials containing substantially no constituents boiling below 300 C. while operating in a system under a pressure of at least 10 atmospheres and a temperature exceeding 250 C.

but below the coking temperature of said.

liquid hydrocarbon materials by continuously passing at least one of said liquid and solid materials through said system and in contact with the other material, contact being effected between said materials until at least 55% of the weight of said solid materials is extracted, introducing additional amounts of said solid and liquid materials into said system and continuously withdrawing the extract from said system.

2. The process for recovering valuable liquid products .from solid bituminous materials which comprises treating said solid materials, in the absence of substantial amounts of hydrogen, with liquid hydrocarbon materials containing substantially no constituents boiling below 300 C. while operating in a system under a pressure of at least 50 atmospheres and a temperature exceeding 250 C.

but below the coking temperature of said liquid hydrocarbon materials by continuously passing at least one of said liquid and solid materials through said system and in contact with the other material, contact being efiected between said materials until at least 55% of the weight of said solid materials is extracted, introducing additional amounts of said solid and liquid materials into said system and continuously withdrawing the extract v from said system.

3. The process for recovering valuable liquid products from solid bituminous materials which comprises treating 'said solid materials, in the absence of substantial amounts of hydrogen, with liquid hydro carbon materials containing substantially no extracted, introducing additional amounts ofsaid solid and liquid materials into said system and continuously withdrawing the extract fromsaid system. I

4. The process as defined in .claim 3 wherein the extraction is efiected in the presence of an indifierent gas not giving rise to substantial amounts of hydrogen under the conditions of working.

5. The process for recovering valuable liquid products from solid bituminous materials which comprises treatin said solid materials, in the absence 0 substantial amounts of hydrogen, and in the presence of a catalyst comprising a sulfide and having an alkaline reaction, with liquid h drocarbon materials containing substantially no constituents boiling below'300 C. while operating in a system under a pressure ofat least 50 atmospheres and a temperature ranging from 250 to 325 C. by continuously passing at least one of said liquid and solid materials through said system and in contact with the other material, contact being effected between said materials until at least 55% of the weight of said solid materials is extracted, introducing additional amounts of said solid-and liquid materials into said system and continuously withdrawing the extract from said system. 5

6. The process as defined in claim 5 wherein said catalyst is selected from the class consisting of the alkali metal and alkaline earth metal sulfides.

7. The process for obtaining valuable liquid products from solid bituminous materials which comprises forming a paste of brown coal and anthracene oil containing substantially no constituents boiling below 300 C. passing said paste in the absence of substantial amounts of hydrogen, in a continuous stream through a coil maintained under a pressure of about 200 atmospheres and a temperature of about 325 0., the coal and oil remaining in contact in said coil until an extraction of at least 65% of the coal is obtained, continuously removing the products of the extraction from the coil and continuousiy feeding additional paste into said coil.

In testimony whereof we have hereunto set our hands. 

